Pressurized refrigeration circulating system



April 25, 1967 Filed May 17, 1965 EVAPORA TOR R. R. ROSS 3,31

PRESSURIZED REFRIGERATION CIRCULATING SYSTEM 4 Sheets-Sheet 1 PESE/PW/kACCl/MULA To? E w -2 W 3 R k E S E 5 ,Zizaczr' 8 foei "i EJ8056- April25, 1967 R. R. RCSS PRESSURIZED REFRIGERATION CIRCULATING SYSTEM 4Sheets-Sheet 2 Filed May 17, 1965 fir/(wafer.

vfigk R. R. ROSS 3,31 PRESSURIZED REFRIGERATION CIRCULATING SYSTEM April25, 1967 4 Sheets-Sheet 3 Filed May 17, 1965 bah kbni xpw WNW YQMKMQQQQQQWWEWQEQU R. R. ROSS April 25, 1967 PRESSURIZED REFRIGERATIONCIRCULATING SYSTEM 4 Sheets-Sheet 4 Filed May 17, 1965 United StatesPatent C) 3,315,484 PRESSURIZED REFRIGERATION CIRCULATING SYSTEM RobertR. Ross, Wheaten, IlL, assignor to H. A. Phillips & Co., Chicago, Ill.,a corporation of Illinois Filed May 17, 1965, Ser. No. 456,136 7 Claims.(Cl. 62-174) The invention relates to refrigerating systems and hasreference more particularly to large capacity industrial typerefrigerating systems wherein it is necessary to protect the compressorof the system from liquid refrigerants such as would otherwise return inthe suction line to the compressor and cause damage to the compressor.

The refrigerant circulating system of the invention is designed forincorporation in the refrigerating system of an industrial plant such asmay operate with multi-stages of compression and with evaporatorsdischarging to the high stage compressor suction as well as to thebooster suction. However, the system may also be applied torefrigeration plants using single stage operation.

An object of the invention is to provide improvements in refrigeratingsystems whereby complete and constant circulation of both the liquid andgaseous refrigerant is accomplished without adding to the powerrequirements of the plant.

Another object of the invention is to provide an ap paratus for thecirculation of the liquid refrigerant in a controlled manner and whichwill be caused to by-pass the compressor of the system so that theevaporators can be operated continuously and in a flooded condition.

Another object of the invention resides in the provision of arefrigerant circulating system of the type as described, having aconstant pressure for feeding liquid refrigerant to a plurality ofevaporators operating at different suction pressures.

A more specific object is to provide a refrigerant circulating systemincorporating the improvements as described and wherein the requiredpressure is produced by using the pressure of the available refrigerantin the system, thus eliminating the need for additional mechanicalpumps.

Other objects and advantages of this invention will be apparent from thefollowing description and the accompanying drawings wherein FIGURE 1 isa diagrammatic view illustrating a refrigerating system havingincorporated therein evaporators and a compressor, together with thenecessary components comprising the improved combination of the invention;

FIGURE 2 is a diagrammatic view of a modified refrigeration system,basically similar to FIGURE 1, but incorporating two separate suctioncircuits at two different suction pressures;

FIGURE 3 is a diagrammatic View of a modified form of the invention, thesame including a system with high and low temperature evaporators withtwo compressors; and

FIGURE 4 is a diagrammatic view of another modified refrigeration systemcoming within the invention.

Referring to FIGURE 1 of the drawings, the numeral indicates the suctionline for returning the evaporated refrigerant from the evaporators tothe compressor 11, the compressor having a high pressure discharge line13. The compressor is conventional in construction and in operation,increasing the pressure of the gas in the suction line which results ina corresponding temperature increase. The high pressure discharge line13 delivers into the condenser 14, having an outlet connection 15leading through line 22 to the receiver 16 and through line 21 to thesuction line accumulator 17. The outlet connection 15 also hasinterposed therein a pilot receiver 18 and with which is combined thehigh side float valve 19 and pilot operated control valve 20, the saidpilot operated control valve being interposed in the connection 21leading to the accumulator 17. The downstream pressure regulating valve23 and the pressure reducing valve 24 are interposed in line 22 leadingto the receiver 16. The pressure in the receiver 16 will be maintainedat a pressure below the condensing pressure (which may be in the rangeof p.s.i.), and above the suction pressure, by means of the downstreampressure regulator 23. It is understood that the receiver pressure willbe maintained at a level sufiicient to allow flow to the evaporators 26through the feed line 25 which is connected to the receiver. Should thereceiver pressure drop below the pressure controlled by the setting ofpressure regulator 23, and valve 24, the regulator 23 will allow a flowof liquid, together with its flash gas, to pass into the receiver tomaintain the pressure. The amount of liquid which passes throughregulator 23 may be less than the amount passing out of the condenser14. This will cause a liquid level rise in pilot receiver 19, which willcause the opening of pilot operated valve 20, and cause some liquid toflow into accumulator 17.

The said accumulator also receives gas, together with the excess liquidwhich passes from the evaporators 26 through 27. The excess liquid istermed the slop over and must by-pass the compressor. Only the gas isreturned by suction line 10 to the compressor 11.

The liquid feed line 25 to the evaporators 26 connects with the receiver16.

The transfer of the liquid refrigerant from the accumulator 17 to thereceiver 16 is accomplished by a return system of the type disclosed andclaimed in the Phillips Patent 2,589,859, granted Mar. 18, 1952, andentitled, Suction Line Liquid Return Trap. Liquid refrigerant flows bygravity from accumulator 17 by means of line 28 to the trap 29. When theliquid level in the trap reaches a predetermined level, the differentialfloat switch 30 will actuate the three-way valve 31 to connect the topof the trap to the discharge of the pressure regulator 23 by means ofline 32. The flash gas flowing from the regulator with the liquid willdisplace the liquid in the trap 29 and force the liquid within the trapinto the receiver 16 through the connecting line 33. Valve 24 whichpermits flow in one direction only to the receiver and which isdownstream of regulator 23 feeding the receiver imposes a pressure dropso that the receiver pressure may be slightly below the set pressure ofregulator 23. This aids in inducing flow to take place from the trap tothe receiver. When the liquid refrigerant in the trap reaches apredetermined low level, the switch 30 will again actuate the three-wayvalve 31 to close line 32 and connect the trap with line 34 leading tothe accumulator 17. With the accumulator and trap thus equalized inpressure, the liquid refrigerant will again flow by gravity into thetrap.

The circulating system of FIGURE 2 is similar in its aspects to thatshown in FIGURE 1 with the exception that another suction line circuitwith a corresponding suction line accumulator 40 and booster compressor41 is added. Liquid is fed to high and low temperature evaporators fromthe receiver 43. Liquid and gas flowing from the low temperatureevaporators 44 pass through line 45 to the low temperature accumulator40. The gas enters suction line 46 and passes to the suction side of thebooster compressor 41. Line 47 connects the discharge side of thebooster compressor to the accumulator 42. Gas from the booster dischargepasses through this line and is desuperheated in the accumulator 42 andis then passed with the gas from the high temperature evaporators to thesuction side of compressor 48.

The excess liquid returning from evaporators 44 passes out ofaccumulator 40, through line 49 into an added second trap 50. Thissecond trap is actuated in the same manner as described for the trap 29in FIGURE 1, but discharges liquidthrough line 51 to accumulator 42.

The circulating system of FIGURE 3 is similar and has the same basiccomponents as FIGURE 2. The only difference is that the liquid to thelow temperature evaporators 44 is fed directly from the accumulator 42through line 62 in which is interposed a sub-cooling coil which passesthrough accumulator 40. This system can be used when the pressure inaccumulator 42 is of sufficient elevation to cause liquid feed to thelow temperature evaporators 44.

The circulating system of FIGURE 4 is similar to that in FIGURE 2. Thetrap 50 connected to low temperature accumulator 40 is actuated in thesame manner as previously described, but discharges the liquid directlyto receiver 43. High side control 70 will be actuated by the liquidlevel in accumulator 42 and will allow the liquid to flow through line71 to accumulator 40 should the liquid in accumulator 42 rise above apredetermined level.

In the refrigerating structure herein described it will be understoodthat the feed line for the evaporators includes the high pressuregaseous line 13, the condenser 14, lines and 22, the receiver 16 andline 25. Since the accumulator 17 is supplied with liquid refrigerant bythe connections 21, it is possible to connect the receiver 16 with thegaseous refrigerant line 13 instead of having line 22coi1nect with 15 asshown. An additional alternative as regards the modification of FIGURE 2resides in the fact that line 51 instead of delivering to theaccumulator 42 can be connected to the receiver 43 for delivery of theliquid refrigerant directly to the receiver.

The invention is not to be limited to or by details' of construction ofthe particular embodiment thereof illustrated by the drawings, asvarious other forms of the device will of course be apparent to thoseskilled in the art without departing from the spirit of the invention ofthe scope of'the claims.

What is claimed is: V

1. In a refrigerating system, in combination, a condenser, anevaporator,a feed line for supplying liquid refrigerant under pressure to saidevaporator in an amount greater than'the evaporator is capable ofevaporating, said feed line including a receiver and said feed lineconnecting the condenser with the receiver, a suction line for drawingoffthe vaporized and liquid refrigerant from the evaporator, anaccumulator in the suction line for trapping the liquid refrigerantpassing through the evaporator, liquid return means including areservoir for receiving and temporarily storing the liquid refrigerantfrom said accumulator, a conduit connecting said reservoir with thereceiver, means operable in response to changes in the level of theliquid in the reservoir, valve means controlled by said liquid levelresponsive means for introducing refrigerant from the feed line of thesystem into the said reservoir to force the liquid from the reservoirinto the receiver for eventual delivery to the evaporator, means forcontrolling receiver pressure including a downstream pressure regulatorlocated in the feed line in advance of the receiver, whereby thereceiver is maintained at a pressure below condenser pressure but aboveevaporator pressure, and conduit means having connection with the feedline between the condenser and the pressure regulator for deliveringliquid refrigerant to the accumulator.

2. A refrigerating system as defined by claim 1 additionally including asecond evaporator and a second accumulator, the second accumulator beinglocated in the suction line of the second evaporator for trapping anyliquid refrigerant passing through the second evaporator, a feed linefor the second evaporator having connection with the first mentionedaccumulator for feeding liquid refrigerant trapped by the firstmentioned accumulator to the second evaporator, said feed line for thesecond evaporator including a coil located in the second accumulatorbelow the level of the liquid refrigerant within the second accumulatorfor cooling the refrigerant flowing in the feed line in advance offeeding the same to the second evaporator, and liquid return means forreturning excess.

liquid refrigerant from the second accumulator to the first mentionedaccumulator. V

' 3. In a refrigerating system, in combination, an evaporator, a feedline for supplying liquid refrigerant under pressure to said evaporatorin an amount greater than the evaporator is capable of evaporating, saidfeed line including a receiver, a suction line'for drawing off thevaporized and liquid refrigerant from the evaporator, an accumulator inthe suction line for trapping the liquid refrigerant passing through theevaporator, liquid return means including a reservoir for receiving andtemporarily storing the liquid refrigerant from said accumulator, aconduit connecting said reservoir with the receiver, means operable inresponse to changes in the level of the liquid in the reservoir, valvemeans controlled by said liquid level responsive means for. introducingrefrigerant from the feed line of the system into said reservoir toforce the liquid from the reservoir into the receiver for eventualdelivery to the evaporator, means for controlling receiver,

pressure including a downstream pressure regulator 'located in the feedline in advance of the receiver, whereby the receiver is maintained at apressure below condensing pressure but above evaporator pressure, asecond evaporator, a second accumulator, the second accumulator beinglocated in the suction line of the second evaporator for trapping anyliquid refrigerant passing through the second evaporator, a feed linefor the second evaporator having connection with the receiver, andliquid return means for returning the excess liquid refrigerant from thesecond accumulator to the first mentioned accumulator.

4. In a refrigerating system, in combination, an evaporator,'a feed linefor supplying liquid refrigerant under pressure to said evaporator in anamount greater than the evaporator is capable of evaporating, said feedline including a receiver, a suction line for drawing offthe vaporizedand liquid refrigerant from the evaporator, an accumulator in thesuction line for trapping the liquid refrigerant passing through theevaporator, means for controlling receiver pressure including adownstream pressure regulator located in the feed line in advance of thereceiver, whereby the receiver is maintained at a pressure belowcondensing pressure but above evaporator pressure,

a second evaporator, a feed line for the second evaporator from thesecond accumulator to the receiver, and conduit means connecting thefirst mentioned accumulator with the second accumulator for supplyingliquid refrigerant in excess of a predetermined amount from the firstmentioned accumulator to the second accumulator.

5. In a refrigerating system, in combination, a condenser, anevaporator, a feed line for supplying liquid refrigerant from thecondenser to the evaporator in an amount greater than the evaporator iscapable of evaporating, said feed line including a receiver, a suctionline for drawing off the vaporized and liquid refrigerant from theevaporator, a first accumulator and a second accumulator, the secondaccumulator having location in the suction line for receiving andtrapping the liquid refrigerant passing through the evaporator, meansfor controlling receiver pressure including a down stream pressureregulator located in the feed line in advance of the receiver, wherebythe receiver is maintained at a pressure below condensing pressure butabove evaporator pressure, conduit means connecting with the feed linebetween the condenser and said pressure regulator for supplying liquidrefrigerantto the ifirst accumulator whereby the first accumulatorreceives and stores liquid refrigerant supplied thereto from thecondenser, a connection between the first accumulator .and the secondaccumulator for supplying liquid refrigerant in excess of apredetermined amount from the first accumulator to the secondaccumulator, and liquid return means for returning the excess liquidrefrigerant from the second accumulator to the receiver.

6. In a refrigerating system, in combination, a condenser, anevaporator, a feed line for supplying liquid refrigerant from thecondenser to the evaporator in an amount greater than the evaporator iscapable of evaporating, said feed line including a receiver, a suctionline for drawing ofit the vaporized and liquid refrigerant from theevaporator, an accumulator in the suction line for trapping the liquidrefrigerant passing through the evaporator, liquid return means forreceiving the liquid refrigerant from the accumulator and for returningthe same to the receiver for eventual delivery to the evaporator, meansfor controlling receiver pressure including a downstream pressureregulator located in the feed line in advance of the receiver, wherebythe receiver is maintained at a pressure below condensing pressure butabove evaporator pressure, and conduit means connecting with the feedline between the condenser and the pressure regulator for deliveringliquid refrigerant to said accumulator.

7. In a refrigerating system as defined by claim 6, additionallyincluding a valve in the feed line between the pressure regulator andthe receiver permitting flow in the direction of the receiver only, saidvalve effecting a pressure drop to maintain the receiver at a pressurebelow the set pressure of the pressure regulator.

References Cited by the Examiner UNITED STATES PATENTS 2,589,859 3/ 1952Phillips 62174 2,778,195 1/1957 Christensen 62l74 2,836,966 6/1958Kocher 62503 X 2,841,962 7/1958 Richards 62l74 2,871,673 2/1959 Richards62l74 2,966,043 12/1960 Ross 62l74 MEYER PERLIN, Primary Examiner.

1. IN A REFRIGERATING SYSTEM, IN COMBINATION, A CONDENSER, ANEVAPORATOR, A FEED LINE FOR SUPPLYING LIQUID REFRIGERANT UNDER PRESSURETO SAID EVAPORATOR IN AN AMOUNT GREATER THAN THE EVAPORATOR IS CAPABLEOF EVAPORATING, SAID FEED LINE INCLUDING A RECEIVER AND SAID FEED LINECONNECTING THE CONDENSER WITH THE RECEIVER, A SUCTION LINE FOR DRAWINGOFF THE VAPORIZED AND LIQUID REFRIGERANT FROM THE EVAPORATOR, ANACCUMULATOR IN THE SUCTION LINE FOR TRAPPING THE LIQUID REFRIGERANTPASSING THROUGH THE EVAPORATOR, LIQUID RETURN MEANS INCLUDING ARESERVOIR FOR RECEIVING AND TEMPORARILY STORING THE LIQUID REFRIGERANTFROM SAID ACCUMULATOR, A CONDUIT CONNECTING SAID RESERVOIR WITH THERECEIVER, MEANS OPERABLE IN RESPONSE TO CHANGES IN THE LEVEL OF THELIQUID IN THE RESERVOIR, VALVE MEANS CONTROLLED BY SAID LIQUID LEVELRESPONSIVE MEANS FOR INTRODUCING REFRIGERANT FROM THE FEED LINE OF THESYSTEM INTO THE SAID RESERVOIR TO FORCE THE LIQUID FROM THE RESERVOIRINTO THE RECEIVER FOR EVENTUAL DELIVERY TO THE EVAPORATOR, MEANS FORCONTROLLING RECEIVER PRESSURE INCLUDING A DOWNSTREAM PRESSURE REGULATORLOCATED IN THE FEED LINE IN ADVANCE OF THE RECEIVER, WHEREBY THERECEIVER IS MAINTAINED AT A PRESSURE BELOW CONDENSER PRESSURE BUT ABOVEEVAPORATOR PRESSURE, AND CONDUIT MEANS HAVING CONNECTION WITH THE FEEDLINE BETWEEN THE CONDENSER AND THE PRESSURE REGULATOR FOR DELIVERINGLIQUID REFRIGERANT TO THE ACCUMULATOR.